On 4/15/2013 9:44 AM, Jan P. Kessler wrote:
localpart case sensivity according to rfc5321:
"The local-part of a mailbox MUST BE treated as case sensitive."
You are misunderstanding. Relaying MTAs MUST treat the local-part as
case sensitive. IOW, until the message is received at the destination,
case must be preserved. However, the RFC does NOT require any
organization to treat their local addresses as case sensitive. It
would be pointless anyway as you could just say all the variations of
case are aliases.
Really? I thought about that, but I think it's not that easy. What if
you are a provider (relaying for one or more organisations) and the
rate-limiting happens at your relay? I know about several providers
using rate limits to throttle their customers on unusual mass-mailing
events. Of course these rate limits will not modify the envelope address
case but nevertheless have consequences depending on their
implementation (means if you count "bob" and "BoB" differently or not).
Again sorry to the list maintainers. If you think, that this is not the
right place for this discussion, anybody is free to share his opinion at
info at postfwd dot org.
Taken strictly, as not being the destination host, the relay would need
to treat the addresses as case-sensitive, at least for relaying
purposes. That said, rate limiting in and of itself would not be
affected by the RFC. IOW, the RFC has absolutely nothing to say about
the matter.
Basically, all the RFC is saying is that a relay cannot assume addresses
are case insensitive and MUST preserve the case of the address in the
envelope. It has no bearing on anything else.
